Fig. 8.

Count rate performance with both systems operating at optimal mode for high count rate using ^99mTc sources. According to NEMA guidelines the incident rate is determined by assuming that it is equal to the rate observed on the camera at low doses, while higher doses are normalized accordingly. The curves demonstrate linear count rate response of the DNM system (blue line) up to the system computer limit and non-linear response with saturation and even paralysis of S-SPECT (pink line). The maximal rate achieved with DNM is almost twice of what can be achieved with S-SPECT. No count loss is noted with DNM, while NEMA criterion for 20% loss was reached at 210 kc/s on S-SPECT